Sorry if this has been covered but I have heard people get into arguments many times over how many times to crank the ignition when doing a compression test. along with what fuses to pull, and ive even heard of people pulling the injectors. the motor has to be warm, thats a given but is there anything else?

 

there is 2 ways you can do it. both are same theory but one is with the motor off and doing the compression off the starter a few times,

and the other is by starting the motor with 1 spark plug out and the compressor in there

the second one gives usually a better reading. Pulling the injectors isn't necessary since you have the compressor in there and running it for about 3 seconds at a time, but you will see the PSI on the gauge go up after about 4 strokes of the piston.

hth

 

that's weird cause i did the same things and i got ridiculously high numbers across each cyl (in the high 200's). I guess it's not bad though because it was even across the board. i might try it again today.

 

So with the other way, how many times do you crank it to find out the actual compression numbers?

 

you keep cranking it until the PSI gauge doesn't go any higher, this determines the maximum PSI for compression.